schmidt



W. SCHMIDT.

MEANS FR SOUL-ING THE PISTONS UF INTERNAL COMBUSUON ENGINES. AFPLzcATloN man 1AN.|H.1916.

@ @Trae/Vix UNITED STATES PATENT OFFICE.

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To all ui/:om it may concern:

Be it known that I, WILnnmr Sculture, o. subject of the German Emperor, King of Prussia, residing Germany, have invented e new und useful Improvement in Moulis for Cooling the Pistons of Internal-Combustion E es, of which the following is especiiication.

My invention relates to internal combustion engines, perticulerl to such engines Kce have means forcooling il eicted ports, und hes, for en object, to .pro vide n novel menus, free from certain diilicnlties hitherto met with, for accomplishing such cooling. i

My invention is `most usefully. embodied in that type o internal combustion engine which is operated in Veornbimition 'witho steam cugino, preferably oi the multi-expension-typc. i

In combustion ycn,. ,fne s the working piston und the cylinder walls are directly exposed to the excessively 4high temperatures of combustion c nd, therefore, themselves tend to nssume :i very high. temperature. A coolinfy of the cylinder wells und particularly, o the piston proper is, there 'ore'.f greatly to be desired.' Se :fer es concerns thepiston, however, structurel end operative difficulties together with the enrolled loss of heet has caused such coolin tised. Fhonldthe dimensions of the combustion cylinder, however.I exceed n certain limit, which limit is nttuincd earlier in ,the cose oi two cycle engines than in the cose of four cycle engines, this piston cooling becomes ebsolutelynecessory. Y

Vl-litherto cooling of the piston has been princilmlly effected by menne oliquids,

water or oil, for exemple; nir hns also been',I

proposed as e substitute for liquids.V In cooling with liquids `the constructions proposed hnve involved considerable complexen ity, particularly as regards the arrangement of the inlet and outlet conduits, which hns affected the certaintyV of o erationof the engine furthermore, liqui wei htin the piston has necessarily increased. e mess of the moving ports and hence disturbed the smooth running oi' the engine. In coohng with ein', on the other hond it Vhas been found impossible to suiiiciently reduce the temperature of the piston.

Furthermore, whether liquid cooling or at CasselWilhelmshhe,

ie vpiston und essoto be very little preccir cooli has been practise in either case there has en no e'eetive ut' ization of the obstructed heut.

,By menus of my invention herein de* scribed the above referred to disudventa s ure-avoided and an eective cooling of t e piston provided, together with en eilicient utilization of the abstracted heet.

Briefly described, my invention comprises c current or currents of exhaust steam as a cooling medium, seid steam being` led through one or more hollowY spaces of the piston. Astheexhaust steam thus fiows over theiurts' heet is abstracted from and s :1s-societe ports cooled 'simultaneously the ihstrwcted heet dries and sulgierhecte` the stenmwhich moy then be Kutlieedineny desired manner, or `the steam may be exhausted to the atmosphere.

My means will befound especially cppliceble to combined combustion and steam engines, particularly when the `steern engine Visy of the multiexpunsion type. In such combination engines the exhaust stoom mcy or from one of the low pressure cy ieders, through the combustion en c iston, from which it abstracts heet which ries and su perhects the steam; the steam is then cerricd to e steam cylinder or c linders of lower pressure. Thus there is so ved the difficult Emblem referred to of dryin and supereoting steam which has :dren y performed Work und of utiliving seid steam' so as to secure n. return from the heat which has been used to perform such drying und superheating.

In cerrying out my invention I prefer to em` loy e, combination .internal combustion en esteem engine which employs e. common cylinderhcving o combustion space et one end `und esteem splice et the other. This niords` the T ndvecntuge4 that the exhaust steam muy be led through the piston by the shortestpossible path.

Such n.- combinationv engine is shown in the accompanying drawing which represents a. central longitudinal section through the common cylinder of e. combined two cycle combustion en ine and c steam engine hevin slotted out ets.

eferring to the drawing u cylinder of uniform diameter has a steam space A at one end and n combustion space B at the other y hc'teken yfrom the high `pressure c liuder,

end. A combined steam and combustion piston is adapted to move in thiseylinder the end D closing the combustion space and lthe other end closin the steam ace. IIhe piston is made ho ow with peripheral slots c openi therefrom near its steam end and other similar slots ,-also opening therefrom but separated from slots c b a partition wail formed as a. tube C which tapers toward and whose o n end terminates near the inner surface o the combustion end D.

Other peripheral slots c are also provided at the very end of the piston which slots open into the steam spaeeA.

An internal annular recess Z1 into which piston slots a and c are ada ted to simultaneously open at the close o the steam ex pansion period, is provided.

An annular channel la., surrounds a 'similar channel into which the exhaust combustion gases are discharged, the two channels having a common separatin wall. The inner wall of each of these ciannels constitutes part of the cylinder wall and in these inner walls .are provided inlet open,- ings f, .for channel 71 and inlet openings lt- -for channel i. The two channels are. also provided with outlet openings g and m respectively. The outlet m is connected by means of pipe n to the valve chest of the lower pressure steam cylinder 11. This cylinder, its valve gear, etc., maybe of any suitable construction.

The operation of m invention is as `follows: In the position s iown in the drawln Y, the steam expansion period being over, bot slots c and c open into recess The ex haust steam,thercfore, streamsthrough these slots, by Iway of recess b, and .up through the tube C against the inner surface of plston combustion end D. Here, it reverses direction and, by reason of the eddymg thereby brought about, brinrfs about an intensive coolin of the combustion end of the iston. 1e steam then passes downwar y over the inner peripheral wall of the piston, cooling it as it goes, and leaves the piston by way of slots e and f, now in coincidence, channel h and outlet As the exhaust steam passes through channel a. it abstracts heat which has been given to the partition wall comi-non to channels It and i by the exhaust combustion gases previously discharged through inlets k-and channel i after the pistonhas made its combustion power stroke. After bein so heated as indicated the steam is carried y pipe a to the low pressurelcylinder p, there to per form additional fork in the usual way.

In the construction of my invention thc steam working space, from which the exhaust steam is to bel taken for cooling purposes, may be determined, according` to the conditions present at the time, either as a slngle working stadge, or as `a hi h pressure or as an inteme late stage. all suon cases it is advisable to determine the exhaust pressure of the combustion ases at something higher than one atmosp ere absoluteas, in this way, any carrying of such gases or of oil residues back into the steam space is avoided.

The. structure illustrated and described may be varied in details within the spirit of my invention. Thus it is not essential that there be but one combined combustion and steam (piston and a common cylinder therefor an steam cylinderand iston may be separated from combustion cyginderand piston if desired. The exhaust inlets and outlets, also, may be valves of any desired type instead of simple slots as shown.

'Iaving described my invention, I claim:

l. In apparatus ofthe class described, 'the combination of n, multi-stage steam cngine,ian internal combustion engine, and means to carry the exhaust steam from an upper stage cylinder into contact withV heated portions of the internal combustion e ine and thereafter to a lower stage steam cy Inder. i

2. In apparatus of the class described, the combination of a multi-stage. steam engine, an internal combustion engine, means to pass the exhaust steam from a steam cfhnder of an uppler stage into contact with t 1e )iston and `en aust passage walls of the com ustion engine, whereb said combustion engine parts are coole and the steam is superheated, and means ,to carry said steam to a steam c linder of lower stage where it is permitte to expand.

3. In apparatus of the class described, the combination of a multistage steam engine, an internal combustion engine, and means to pass the exhaust steam from a steam cylinder of an upper stage to one of lower stage through a conduit comprising the hollow interior of4 the internal con'ilnis-` tion engine piston.

In testimony whereof I' have hereunto set' my hand in the preseneeof two subscribing witnesses.

WILHELM SCHMIDT.

Witnesses:

(Jrcfs'rnv Tamm, JEAN GRUND. 

